ES2356791T3 - EXTRACTION SYSTEM FOR THE PREPARATION OF A DRINK FROM A CARTRIDGE. - Google Patents

Abstract

Extraction system (1) for preparing a beverage from a cartridge that uses a fluid injected under pressure in said cartridge and comprising: - a cartridge (3) comprising: A beverage supply wall (15) that can be perforated under The effect of fluid pressure inside the cartridge, A wall (13) to inject the fluid into the cartridge, A clamping region (16) formed from an edge that runs radially around the periphery of the cartridge, - An extraction device (2) intended to accept said cartridge and comprising: An injection cell (4, 40) comprising fluid injection means (8, 9, 51, 52, 62, 70), and a cartridge holder (5, 48) comprising piercing means (12, 60) for perforating the supply wall (15) of the cartridge under the effect of fluid pressure in the cartridge; said injection cell (4, 40) and said cartridge holder (5, 48) being arranged such that they move relative to each other by a closing device (28, 46) that closes them around the cartridge before the injection, and catches the cartridge in said holding region, in which the injection cell (4, 40) comprises a base (19, 42) and a closing piston unit (20, 41) that is mounted so that it can move axially with respect to said base; said closing piston unit (20, 41) can move relative to the base (19, 42) under the effect of the pressure of the fluid against the holding region of the cartridge (16) to generate grip forces that prevent the injection cell and the cartridge holder open in relation to each other as the system is pressurized, characterized in that the cartridge comprises sealing means (17), made of deformable material, belonging to the cartridge or attached to this and whose grip forces of the piston unit (20, 41) are applied and have the shape of a joint that occupies all or part of the edge.

Description

The invention relates to the field of preparing beverages from cartridges in an extraction device designed to accept said cartridge; the cartridge / device assembly being usually qualified as the "system" of extraction. 5

The technological background of the invention relates to the field of cartridges containing edible ingredients such as ground coffee and which are extracted under hot water pressure in an extraction device. Hot water is injected into the cartridge via an injection face that uses a perforation system, for example, the fluid pressure is increased in the cartridge until another face of the cartridge is perforated with drilling means under the effect of pressure so that the extract is supplied from the cartridge. A multitude of reliefs that belong to the drilling means allows the formation of controlled openings in the face of the cartridge while at the same time filtering the extract sufficiently so that the coffee beans are kept inside the cartridge.

A system employing this method is known, for example, in EP-A-512470.

EP 1 654 966 proposes an improvement to provide a better seal after closing the extraction system so as to better control the characteristics of the extraction, in particular the pressures of the opening and the extraction. To do this, the cartridge is equipped with a attached closure or a closure that forms an integral part of the cartridge so that each new cartridge removed seals perfectly in the extraction system, thus avoiding any risk of water loss through the region of cartridge holder out. In known systems, the closure is generally supported by the device, and problems of wear and dirt may be present that can cause the extraction conditions to vary. Another advantage of the invention is that it allows the cartridge to be released more easily by preventing the cartridge from "sticking" in the cartridge cell through the suction or vacuum effect. To do so, the invention can provide air passages such as grooves on the support surface of the cartridge cell.

In order to obtain a satisfactory seal, the closure supported by the cartridge needs to include a sufficient thickness of deformable material. This closure needs to have dimensions such that it is sufficiently compressed to fully compensate for any separation after closure and when the device is at maximum pressure during removal. Now, it has been observed that the injection pressure, which can be as much as 12-20 bar, tends, at these high pressure levels, to cause the device to open by the order of a few tenths of a millimeter in the clamping region of the cartridge. This seal therefore needs to be able to compensate for such "dynamic" separation. If the seal is not high enough, then there is insufficient compensation and losses occur, which means that the increase in pressure in the cartridge cannot take place correctly.

However, increasing the thickness of the seal to solve this separation problem leads to additional costs in the production of the cartridge.

WO 2006/003116 refers to a filtering machine for producing beverages using a sealed capsule of anhydrous powder material. The capsule is a standard sealed capsule and fluid adjustment is obtained with a pressure-tight seal 35 of a hydraulically assisted spray that presses against the capsule flange.

In particular, one of the objects of the invention is to maintain the advantages of a closure associated with the cartridge while at the same time providing a solution to the problem of dynamic separation under the effect of internal pressure during extraction.

To do so, the invention relates to an extraction system for preparing a beverage according to claim 1.

According to the invention, the gasket of the cartridge forms a thickness of material that can be deformed under the effect of being trapped in the device.

As a preference, the gasket is softer than the cartridge holder with which the gasket is in contact in the cartridge holding region and the piston unit holding surface. For example, the support is usually a clamping edge of the cartridge. The clamping surface of the piston unit can be made of a rigid material such as metal or a plastic that cannot be deformed under the effect of the closing forces and the heat of the fluid.

The joint preferably has a thickness of 0.8mm or less, and preferably, a thickness between 0.2 and 0.6mm. A thickness with this order of magnitude makes it possible to avoid using a closure in the device while at the same time offering a dynamic closure capable of withstanding high pressures, for example, pressures in the range between 12 and 20 bar.

The gasket of the cartridge can be made of an elastically deformable material to more easily compensate for any possible opening in the clamping surface of the cartridge cell. Material examples

deformable for closure may include elastomeric materials such as TPE (thermoplastic elastomer), LSR (liquid silicone rubber), silicone or EPDM.

In some cases, the joint can also be made of deformable but slightly elastic material, such as synthetic fibers, cellulose, foam, plastic or mastics.

The gasket can be an element that is prefabricated and mounted with the cartridge with any means of connection or alternatively it can be co-manufactured with the cartridge. The seal can be an O-ring mounted with the cartridge. It can be fixed to the cartridge by joining, welding or any other means of connection. It can also be deposited in liquid form and polymerized in situ or co-injected or over-injected according to the material from which the cartridge is made. The gasket can also form an integral part of a cartridge wall and be formed of the same material, for example plastic. 10

With regard to the extraction device, it comprises an injection cell comprising a base and a closing piston unit. The closing piston unit is able to move with respect to the base under the effect of the fluid after injection.

The injection cell generally comprises an internal extraction cavity with a shape designed to at least partially accept the contour of a cartridge, at least one fluid supply conduit that supplies the cavity with fluid, possibly at least opening means , such as piercing elements, allowing the cartridge to be opened so that fluid can be introduced into the cartridge.

The term "fluid" refers more particularly to hot water but does not rule out the use of other liquids, such as liquid foods.

According to one characteristic, the piston unit is mounted with respect to the base so that it moves coaxially with it; said unit defining, with the base, a pressure chamber whose volume can be expanded; the expansion of the pressure chamber under the effect of the fluid having the effect of driving said piston unit back towards the cartridge, and said unit comprising a clamping surface that exerts closing forces against the closure of the cartridge in the region of holding the cartridge under the effect of the thrust exerted by the fluid on the piston unit. 25

According to a feature of the invention, to provide a seal between the pressure chamber and the outside, at least some sealing means are provided between the piston unit and the base.

According to another characteristic, incompressible elastic thrust means are provided in the pressure chamber and are elastically deformable and at least partially occupy the pressure chamber; These elastic means are arranged in the pressure chamber in such a way that they are deformed by the fluid and thus are capable of applying axial thrust forces against the action of the piston unit. According to a possible embodiment, the elastic means completely occupy the pressure chamber when the pressure chamber is in the resting position. The objective is to reduce the volume occupied by the fluid in the pressure chamber that replaces its volume with elastic means. The elastic thrust means absorb the forces exerted by the pressurized fluid and transmits them to the piston unit. The advantages are better ability to control the closing forces (for example by providing materials of different hardnesses), reducing stagnation regions and preventing the pressure chamber from becoming dirty with food waste such as coffee beans.

The incompressible elastic pushing means can thus be made of silicone or some other elastomer. The hardness of such material is adjusted to suit the desired operation and the desired closing forces to be transmitted. 40

According to a possible embodiment, the incompressible elastic thrust means comprise a first surface on which the fluid pressure is exerted, which extends radially, and a second thrust surface that extends transversely so as to exert an axial thrust on the piston unit

According to a possible embodiment, the sealing means and the elastic means are one and the same element. Four. Five

The thrust (projected) surface of the piston unit, on whose surface the pressure of the fluid is exerted outside the cartridge in order to make the closure is greater than the supply surface of the cartridge. As a result, by providing a ratio of surface areas that is always in favor of the pushing surface, the separation forces that tend to attempt to open the device remain inferior to the forces that close the device around the cartridge. As a preference, the thrust surface is about 1.2 to 2 times the size of the supply surface.

According to a first embodiment, the pressure chamber forms a continuation of the extraction cavity. The pressure chamber is then fed directly with fluid through at least one opening or a channel in the extraction cavity. The pressure chamber is preferably an annular continuation of the extraction cavity. 55

In this case, the piston unit partially constitutes the extraction cavity so that the piston unit and the base together define the surfaces of the extraction cavity. In this case, the base comprises a fluid supply conduit that communicates directly with the extraction cavity. The base also preferably comprises at least opening means, such as a piercing element, for example, that projects into the extraction cavity. The piston unit preferably constitutes the lower (holding) part 5 of the extraction cavity. Next, it comprises at least one substantially cylindrical or frustoconical part that fits internally with the external shape of the cartridge. In this case, the pressure chamber is preferably a substantially annular chamber positioned around the extraction cavity to extend it radially. A configuration like this allows the volume of the device to be greatly reduced.

According to this same embodiment, the fluid is supplied to the pressure chamber by a plurality of 10 openings or channels positioned radially between the extraction cavity and the annular pressure chamber. An arrangement such as this makes it possible to guarantee a uniform increase in pressure in the chamber and, therefore, that the closing forces are well distributed around the periphery of the clamping surface. For example, the channels have an open configuration and are arranged on one of the edges between the piston unit and the base so that they possibly prevent them from being blocked with solid or scaled coffee particles. In this case, as the piston unit gradually moves away from the base, the openings or channels become larger and the supply surface of the chamber increases accordingly.

According to a second possible embodiment, the pressure chamber extends upstream of the extraction cavity.

In this case, the piston unit can completely form the extraction cavity to accept the cartridge 20 so that the cavity of the piston unit is able to move relative to a base. In this case, the pressure chamber is supplied via at least one fluid channel located at the base and course above the chamber. The extraction cavity is then supplied via the pressure chamber through at least one fluid channel formed along the piston unit.

According to another advantage, means are provided for decoupling the cartridge, thus avoiding a vacuum effect in the holding region. To do this, the clamping surface of the piston unit preferably forms discontinuous clamping sections to trap the clamping region of the cartridge.

In particular, the clamping surface of the piston unit comprises open grooves that extend radially and separate said discontinuous sections. The size of the slots depends on the size of the cartridge seal. As a preference, the grooves have a height that can be compensated with the thickness of the joint, whose height is less than the thickness of the joint. Preferably, the height (H) of the grooves is equal to less than 2/3 of the thickness of the joint, preferably equal to about half of the thickness of the joint. For example, the height of the groove is approximately 0.1 to 0.4mm. The width of the groove is also preferably between about 0.8 and 3 mm.

The extraction device is associated with a closing device to close the injection cell and the extraction support around the cartridge before the pressure is increased. This closure can be considered as a "pre-closure" as long as a certain closing force is applied to the cartridge in the holding region by the device before the fluid pressurizes it. The closing device can be a hydromechanical or hydraulic device, or a mechanical device. It can also be a manually operated system or a motor driven system.

The invention will be better understood and other features will be apparent from the detailed description of the attached drawings.

Brief description of the drawings

Figure 1 is a sectional and perspective view of the extraction system according to the invention, showing the system in a first operating state, in particular in the opening mode with the placement of a cartridge in the extraction device ; Four. Five

Figure 2 is a perspective view of part of the system in its state in accordance with Figure 1;

Figure 3 is a view similar to Figure 2 but in a second operating state, in particular in the closing mode and before the system is pressurized;

Figure 4 is a detailed sectional view of the system in the closed state according to Figure 3;

Figure 5 is a sectional and perspective view of the extraction system in a third state of operation, in particular when the system is under pressure;

Figure 6 is a detailed perspective view of the system under extraction pressure (without the cartridge membrane);

Figure 7 is a cross-sectional side view of an extraction system according to a second

embodiment representing the invention in the mode of opening and placing a cartridge in the extraction device;

Figure 8 is a detailed sectional view of the system after mechanical closure but before the system is pressurized;

Figure 9 is a detailed sectional view of the system whose system is pressurized; 5

Figure 10 is a detailed sectional view of a third embodiment after mechanical closure but before the system is pressurized;

Figure 11 is a detailed sectional view according to the embodiment of Figure 10, once the system has been pressurized.

Detailed Description of the Invention 10

With reference to Figures 1 and 2, the extraction system 1 according to the invention, as set forth by means of a non-limiting example, is made of an extraction device 2 in which a cartridge 3 containing a cartridge is housed. Food ingredient to prepare a drink.

The preparation is usually obtained by injecting a pressurized fluid into the cartridge and by extracting the ingredient under the pressure of this fluid. The cartridge is a disposable cartridge and the used cartridge is therefore generally disposed of or recycled. A new cartridge is then placed in the device.

The set "device-cartridge" is known as the "extraction system" in the context of the present application. As will be obvious from what follows in the description, the device and the cartridge constitute means that cannot function without each other and that interact physically and complement each other to extract the liquid extract that is intended to form the beverage. twenty

The extraction device as such is a mounting comprising an injection cell 4 and a cartridge holder 5. The injection cell and the cartridge holder are able to move relative to each other to close around the cartridge 3. In this example , the injection cell 4 is mounted on an upper mobile structure 6A, while the cartridge holder 5 is mounted on a fixed lower structure 6B; the upper structure moving closer to the lower structure through a pivoting movement about an axis of articulation 7. The opposite could be anticipated, ie a cartridge cell that was fixed and a cartridge holder that was capable of moving or alternatively, they could anticipate for the two sides to move towards each other. The dynamics that govern the closure of the injection cell and the cartridge holder are subject to numerous possible variants. In fact, the dynamics in which the parts approach together in a linear path (instead of a non-linear curve) is a possible variant. 30

The injection cell means the part that contains means for injecting a pressurized fluid into the cartridge. These means usually comprise at least one main fluid supply conduit 8 and means for opening the cartridge. The opening means can be, for example, piercing elements 9 whose function is to create one or more openings in the cartridge to allow fluid. The drilling means can be separated from the conduit 8, as illustrated. They can, for example, be blade-shaped elements, needles or spikes. In a variant, the conduit can continue through the piercing element. Other opening means can be anticipated, depending on the nature of the cartridge.

The injection cell has an integral cavity 10 that accepts the injection face of the cartridge after closing. The internal cavity 10 may vary in depth depending on the shape of the cartridge. The free end of the cell has a clamping surface 11. The injection cell is connected to a system for supplying the device with fluid which, in Figure 1, is represented only in part for reasons of simplicity. The fluid supply system generally comprises a water tank, a pressure pump and conduits for transporting the fluid, a water heater, such as a thermoblock, for example, for transporting the fluid at the desired temperature for extraction. The pump can be an electromagnetic piston pump capable of developing a static pressure of several bars or any other type of equivalent pump. Four. Five

The support for the cartridge 5 has an extraction surface 60 that allows the cartridge to be perforated under the effect of increasing pressure on the cartridge. To do this, the surface has at least one relief, preferably a series of reliefs 12, forming perforation means of the cartridge. The reliefs can be differentiated in geometry according to the type of cartridge and the desired extraction conditions. In the example, each relief has the shape of a truncated pyramid. A network of channels 61 is formed through which the liquid extract can flow between the relief structure so that the fluid can be collected in a container (cup or the like).

As shown in Figure 2, the cartridge 3 according to the system of the invention has an injection wall 13 that can be closed while the cartridge is placed or deposited in the device. The injection wall can be formed in a convex body 14 (for example, in a frustoconical shape). The cartridge has a wall 55

of supply 15 through which the extract needs to be able to flow once the openings have been made through the drilling means 12 of the support extraction surface. A wall 15 like this can be a membrane made of aluminum, plastic or plastic / aluminum sheet and can be perforated. For example, the wall is an aluminum sheet with a few tenths of a micron thickness that tears when it reaches its breaking tension after contacting the reliefs 12 at a pressure that can be between 6 and 20 bars depending on the cartridge, the ingredients and the thickness of the membrane. The body of the cartridge can be made of a rigid or semi-rigid material such as aluminum, plastic or a plastic-aluminum sheet.

The cartridge comprises a holding region 16 which is trapped when the device is closed in the cartridge. The entrapment is achieved by bringing the injection cell 4 and the extraction support 5 together and then hugging them both on either side of the holding region 16. The holding region 16 is formed 10 of an edge that runs radially around the periphery of the cartridge. The edge may, at least in part, be formed from the body of the cartridge. The membrane 15 can be mounted with the lower edge of the edge in the clamping region 16 by sealing or welding. In accordance with the invention, the fastening region comprises sealing means in the form of a sealing gasket 17 that occupies all or part of the edge. The seal 17 is preferably an element made of a deformable material that is relatively soft and is engaged or fixed against the flange. A relatively soft material is understood as a material capable of deforming to thereby compensate for at least any opening of the injection cell in the clamping surface that will be explained hereinafter. As a preference, the seal of an elastic material such as an elastomer. The thickness of the seal is preferably 0.8mm or less.

The shape of the joint can be designed in such a way that it favors the advance as the pressure rises, so that providing a better closure uses a minimum amount of material. In the illustrated example, the sealing gasket has a greater thickness on the flange facing the wall of the body 14 of the cartridge than towards the free end of the flange, thus allowing the material to move outward under the effect of the pressure of the fluid that pushes against the cavity and the wall of the cartridge. The thickness of the joint on the side wall can be approximately 0.5mm and decreases outward towards a value between 0 and 0.2mm. The flange of the cartridge 25 can end in a corrugated fold 18 as per se known, and whose entrapment forces are not applied theoretically.

According to the invention, the injection cell is designed to be pressurized such that it increases the closing forces against the holding region after the device has been mechanically closed. To do this, the injection cell comprises a base 19 and a piston unit 20 that is axially mounted with respect to the base with the controlled movement capacity. As shown in Figures 3 and 4, the piston unit comprises a side flange 21 that fits into a groove 22 formed in the base 19. The flange / groove assembly defines a pressure chamber 23 whose volume can be expanded. The chamber may be partially occupied by sealing means 24, such as an elastic block that seals the chamber against the outside in the flange / groove shell. The fluid is transported into the chamber from the internal extraction cavity 35 through start channels or channels 25. These can, for example, be formed in line 26 where the piston unit and the base that forms the upper part of the cavity are find. In the illustrated example, start channels are provided that form notches that widen into the cavity and are positioned on the upper flange of the piston unit 20. They could also be formed at least partially on the lower flange of the base. The start channels or channels 25 are arranged radially and evenly distributed around the periphery of the cavity so that they balance the pressurization of the chamber and allow the piston unit to move linearly along the base.

The device also comprises means 27 for collecting and supplying the liquid extract, these being positioned downstream of the extraction support (Figures 1 and 5). These means, per se known, for example, comprise a funnel-shaped collector and possibly a jet-regulated element.

The device is equipped with a mechanical closing device 28 which is known. A device like this does not need to be described in detail in this application. It can be based on a mechanism for transmitting a force from a manual lever 29 or engine (not shown) to a structure that supports the injection cell. A mechanism such as this can be a mechanism that employs the principle of a latch-lock lever such as, for example, that described in patents EP 1090574 or alternatively EP 1495702. It can also be a cam mechanism, a mechanism that involves an electromagnetic field (solenoid) and / or a hydraulic mechanism. fifty

Figures 3 and 4 show the extraction system after the device around the cartridge has been closed using the closure device 28. The lever 29 is actuated to bring the injection cell 4 closer to the extraction support to the point where the holding region 16 of the cartridge is firmly trapped. In this operating state, the cavity moves towards the cartridge, thereby forcing the piercing elements 9 through the injection wall of the cartridge 3. 55

As shown in Figure 4, the piston unit extends towards its free end 30 through a clamping surface 11 that applies gripping forces to the cartridge seal as a result of mechanical closure. It should be noted that the board is preloaded and compressed to a certain degree. The extraction support serves to produce opposing forces to trap the flange and immobilize the cartridge in said region.

As a preference, the clamping surface 11 has discontinuous clamping sections that delimit grooves 31 between them (Figure 1) that run in the radial direction with respect to the axial line I of the revolution surface formed by the extraction cavity. The number of grooves 31 may vary but, preferably, it is greater than 10, even greater than 20. The grooves are preferably distributed around the entire periphery of the clamping surface. 5

Also as a preference, the end of the piston unit ends at a clamping surface with internal and external edges 32 that converge towards each other to form a localized surface 11 and relatively narrow. The width of the clamping surface 11 is preferably equal to 1mm or less. Similarly, the clamping surface preferably exerts forces closer to the side wall of the cartridge body than the free edge of the edge. The narrow width of the clamping surface means that locally higher forces 10 can be applied and also make it possible to minimize the thickness and / or width of the joint while at the same time ensuring a good seal. As a preference, the inner edge 32 makes an angle A smaller than the angle B of the outer edge 33 (A and B being referenced with respect to axis I). The angle A is preferably between 5 and 10 degrees while the angle B is between 30 and 60 degrees.

In the operating state of Figures 3 and 4, fluid has not yet been injected through the conduit and the piston unit is in the retracted position. Pressure chamber 23 has not yet been subjected to fluid pressure.

Figures 5 and 6 show the next extraction step. An injection fluid is sent through the supply line 8 with a pump of the device until the pressure in the cartridge 3 and the internal cavity is increased. Pressurized fluid fills the cavity, the cartridge and the pressure chamber through the starter ducts 20 and along the encounter line 26 as the piston unit moves to close against the gasket and the flange of the cartridge . The pressure chamber expands under the effect of pressurizing the fluid in the cavity and in the cartridge. The axial surface projected on the pressure chamber is appreciably larger than the supply surface of the cartridge which means that the grip forces exerted on the clamping surface by the piston unit always remain higher than the separation forces exerted on the clamping region although about 25 the side of the internal cavity (between the wall of the cartridge and the cavity). In this way, the closure created is maintained during the extraction process.

During the extraction process, thanks to the fact that the tightness is maintained, the pressure exerted on the membrane against the reliefs reaches a value (located between about 6 and 20 bar depending on the cartridge) such that it leads to the tearing of the membrane against the reliefs reaching the breaking stress of the membrane material. The membrane, therefore, tears in a controlled and localized way to form openings in the corners of the reliefs. In some cases, the pressure in the cartridge may continue to increase appreciably due to any possible compaction of the coffee bed in the cartridge. The extraction is filtered by the membrane and the reliefs. The extract is collected in the channels of the extraction support up to the holes (not shown) made through the sides of the support. 35

Figures 7 to 9 show another possible embodiment in which the injection cell 40 is formed by a piston unit 41 that is axially guided in a base 42, said piston unit 41 completely forming the internal cavity 43. The cartridge 3 by its part is identical to the system of the preceding embodiment.

The injection cell 40 is mounted such that it can move in a structure 44 between an open position (figure 7) and a mechanically closed position (figure 8). The injection cell is thus supported and guided in its movement by guiding means 45 formed on the sides of the structure and which complement the guiding means of the cell (for example, a groove / rib assembly) thus allowing it to move from one position to another by actuating a closing device 46. The closing device is of the type of locking lever with latch (not shown). A cartridge holder 47 is provided, and the cartridge will rest against it once the injection cell 40 has closed and the holding region 16 of the cartridge has been trapped. Four. Five

The support for the cartridge 47 comprises a relief structure 48 for opening the supply side of the cartridge, and identical to that of the previous embodiment.

As before, the mobile piston unit 41 has a solid clamping surface 49 that puts pressure on the gasket of the cartridge 17.

As shown in Figure 8, the piston unit comprises radial grooves 50 that act as 50 start channels for the passage of fluid and the creation of a pressure chamber 56 between the piston unit and the base. The grooves 50 extend from a central supply conduit 51 formed in the piston unit. The central duct 51 communicates with a main supply duct 52 formed in the base 42, and supplied with pressurized fluid supply means located further upstream (pump, water heater, etc.).

A seal 53, such as an O-ring, is also provided between the base and the piston unit that prevents any outward loss. For this, the piston unit comprises an annular groove in which the O-ring is housed. Similarly, the stroke of the piston unit is controlled with stop means between the base and the unit. There are, for example, pins 54 that run in grooves 55 of the base. This makes it possible to prevent the

piston unit is disengaged from the base.

The piston unit 41 of the injection cell is bell-shaped comprising a closed end in which means 62 are formed that pierce the injection face of the cartridge.

In the operating state of Figure 8, the injection cell is closed against the cartridge and the extraction support by the closing means 46. Only the mechanical pressure of the clamping surface 49 of the 5-piston unit is exerted on the cartridge seal 17.

In the operating state of Figure 9, the system is pressurized with fluid and the piston unit is driven back, exerting additional gripping forces on the gasket of the cartridge 17.

Figures 10 and 11 illustrate another alternative way in which the pressure chamber is occupied by incompressible elastic thrust means 57. These means occupy the pressure chamber in the retracted position (that is, before pressurization is performed. ). The incompressible elastic thrust means 57 comprise a first surface 58 on which the pressure of the fluid is exerted and that extends radially, and a second thrust surface 59 that extends transversely to exert an axial thrust on the piston unit 41. The pushing surface 58 delimits an expansion conduit 70 that passes through the unit to allow fluid to pass into the internal cavity. The external surface of the unit on the side opposite surface 58 is, in turn, blocked by the internal surface of the piston unit. Therefore, the unit has a tendency to deform, thereby exerting an axial thrust.

Incompressible elastic pushing means such as these may be a block of relatively deformable incompressible material. Since the block is made of a deformable material, such as a silicone elastomer and occupies substantially the entire volume of the pressure chamber, it undergoes a deformation thrust in a substantially radial direction of the conduit 70 (Figure 11) from a resting position (figure 10). The initial thrust surface on which the fluid pressure is exerted is substantially equal in size to the inner annular surface of the elastomer block. The fluid thrust is therefore substantially radial. Since a block like this is incompressible, its outer surface is compressed against the inner surface and the end surface of the piston unit such that an axial thrust is absorbed perpendicular to the radial thrust of the fluid and therefore exerts on the piston unit in the direction of the clamping region 16. The piston unit 41 therefore moves towards the clamping region, exerting forces that cause the closure against the seal 17.

In general, the invention can be applied to any mechanical device to close the extraction device to reduce the closing forces. For example, reduction in closing forces is possible when using a motor instead of a manually operated closing device (such as a lever). The assistance allows the force necessary for the mechanical seal to be considerably reduced. This request can be provided for an extraction system that uses cartridges with or without seals. In the case of cartridges without sealing, the sealing is then achieved with a gasket formed in the injection cell.

Claims (24)

1. Extraction system (1) for preparing a beverage from a cartridge that uses a fluid injected under pressure in said cartridge and comprising: - a cartridge (3) comprising: 5 A beverage supply wall (15) that can be perforated under the effect of fluid pressure inside the cartridge, A wall (13) to inject the fluid into the cartridge, A clamping region (16) formed of an edge that runs radially around the periphery of the cartridge, 10 - An extraction device (2) intended to accept said cartridge and comprising: An injection cell (4, 40) comprising fluid injection means (8, 9, 51, 52, 62, 70), and a cartridge holder (5, 48) comprising perforation means (12, 60) for perforating the supply wall (15) of the cartridge under the effect of fluid pressure in the cartridge; said injection cell (4, 40) and said cartridge holder (5, 48) being arranged such that they move relative to each other by a closing device (28, 46) that closes them around the cartridge before the injection, and catches the cartridge in said holding region, wherein the injection cell (4, 40) comprises a base (19, 42) and a closing piston unit (20, 41) that is mounted so that it can move axially with respect to said base; said closing piston unit (20, 41) can move relative to the base (19, 42) under the effect of the pressure of the fluid against the holding region of the cartridge (16) to generate grip forces that prevent the injection cell and the cartridge holder open relative to each other as the system is pressurized, characterized in that the cartridge comprises sealing means (17), made of deformable material, belonging to the cartridge or attached to it and whose grip forces of the piston unit (20, 41) are applied and have the shape of a joint that occupies all or part of the edge. 25 2. Extraction system according to claim 1, characterized in that the joint occupies a part of the edge. 3. Extraction system according to claims 1 or 2, characterized in that the supply wall (15) is a membrane mounted with the lower part of the edge in the fastening region by sealing or welding. 30 4. Extraction system according to any of claims 1 to 3, characterized in that the sealing means (17) are a joint that forms a thickness of material that deforms under the effect of being trapped in the device. 5. Extraction system according to claim 4, characterized in that the seal is softer than the cartridge holder whose seal is in contact in the clamping region and the clamping surface of the piston unit 35. 6. Extraction system according to any of claims 4 or 5, characterized in that the sealing means of the cartridge (17) is a gasket with a thickness of 0.8mm or less. 7. Extraction system according to claim 6, characterized in that the sealing means of the cartridge (17) is a joint with a thickness between about 0.2 and 0.6mm. 40 8. Extraction system according to any of claims 1 to 7, characterized in that the sealing means are made of an elastically deformable material to more easily compensate for any possible opening in the clamping surface of the cartridge cell, in in particular, an elastomeric material such as TPE (thermoplastic elastomer), LSR (liquid silicone rubber), silicone or EPDM. 9. Extraction system according to any of claims 1 to 7, characterized in that the sealing means are made of a deformable but slightly elastic material, such as synthetic fibers, cellulose, foam, plastic or mastics. 10. Extraction system according to any of claims 1 to 7, characterized in that the seal is formed of an integral part of the cartridge wall and is formed of the same material such as plastic. 11. Extraction system according to any of the preceding claims, characterized in that the piston unit comprises a clamping surface (11) of a width of 1mm or less. 12. Extraction system according to any of the preceding claims, characterized in that the injection cell (4, 48) comprises an internal extraction cavity (10, 43) in a manner designed to at least partially accept the cartridge. 5 13. Extraction system according to claim 12, characterized in that the cavity (10, 43) comprises at least one fluid supply conduit (8, 51) and possibly at least one opening element (9, 62) . 14. Extraction system according to claims 12 or 13, characterized in that the injection cell comprises a pressure chamber (23, 56). 10 15. Extraction system according to claim 14, characterized in that the pressure chamber (23, 56) is at least partially occupied with elastic thrust means. 16. Extraction system according to claim 15, characterized in that the pressure chamber (23, 56) at rest is completely occupied by elastic thrust means (57). 17. Extraction system according to claims 14, 15 or 16, characterized in that the pressure chamber 15 (23) forms an extension of the extraction cavity (10). 18. Extraction system according to claim 17, characterized in that the pressure chamber (23) forms an annular extension of the extraction cavity (10). 19. Extraction system according to claim 17 or 18, characterized in that the pressure chamber (23) communicates with the extraction cavity (10) via at least one opening or start channel or channel (25). twenty 20. Extraction system according to claim 19, characterized in that the fluid is supplied to the pressure chamber by a plurality of openings or start channels or channels (25) positioned radially between the extraction cavity (10) and the pressure chamber (23). 21. Extraction system according to claims 14, 15 or 16, characterized in that the pressure chamber (56, 58) extends upstream of the extraction cavity (43). 25 22. Extraction system according to any of the preceding claims, characterized in that the clamping surface (11) of the piston unit forms discontinuous pressure surface sections to press against the region of clamping the cartridge. 23. Extraction system according to claim 22, characterized in that the piston unit comprises a clamping surface (11) comprising open slots (31) extending radially and 30 separating said discontinuous clamping sections. 24. Use of the cartridge (3) in the extraction system (1) according to any of the preceding claims 1 to 23 to prepare a beverage.